First Commercially Viable Flexible Nanogenerator Announced
The first commercially viable nanogenerator has been developed, scientists from Georgia Institute of Technology are reporting. The flexible chip can use body movements, in this case a finger pinch, but soon a pulse beat or breathing, for generating electricity.
The device’s power output has been raised by thousands of times and its voltage by 150 times to at last move it out of the lab and toward everyday applications.
“This development represents a milestone toward producing portable electronics that can be powered by body movements without the use of batteries or electrical outlets,” said lead scientist Zhong Lin Wang, Ph.D. “Our nanogenerators are poised to change lives in the future. Their potential is only limited by one’s imagination.”
Capacitor Stores Charge
A nanogenerator powerful enough to drive commercial liquid-crystal displays, light-emitting diodes and laser diodes is the result of the latest improvements. Via storage of the generated charges using a capacitor, the output power is capable to periodically drive a sensor and transmit the signal wirelessly.
“If we can sustain the rate of improvement, the nanogenerator may find a broad range of other applications that require more power,” Wang said.
For example, personal electronic devices powered by footsteps activating nanogenerators inside the sole of a shoe, implanted insulin pumps powered by a heartbeat, and environmental sensors powered by nanogenerators flapping in the breeze could be possible.
Zinc Oxide Nanowires
Zinc oxide (ZnO) nanowires are central to the technology. ZnO nanowires are piezoelectric, meaning they can generate an electric current when strained or flexed. That movement can be practically any body movement, like walking, your heartbeat, or blood flowing through your body.
Zinc oxide nanowires can also generate electricity in response to wind, rolling tires, or many other kinds of movement.
The diameter of a ZnO nanowire is tiny. 500 of the wires can fit inside the width of a single human hair. Wang’s team devised a way to capture and combine the electrical charges from millions of the nanoscale zinc oxide wires.
They also pioneered an efficient way to deposit the nanowires onto flexible polymer chips, each about a quarter the size of a postage stamp. Five nanogenerators stacked together produce about 1 micro Ampere output current at 3 volts, about the same voltage generated by two regular AA batteries, which are about 1.5 volts each.
“While a few volts may not seem like much, it has grown by leaps and bounds over previous versions of the nanogenerator,” said Wang. “Additional nanowires and more nanogenerators, stacked together, could produce enough energy for powering larger electronics, such as an iPod or charging a cell phone.”
Image Credit: Zhong Lin Wang, Ph.D., Georgia Institute of Technology